1. Technical Field of the Invention
The present invention relates to a device and method of segmenting a viewing area of a three-dimensional direct volume display.
2. Description of Related Art
The human visual system uses both physiological and psychological depth cues in determining relative positions of objects in a three-dimensional (3D) scene. Physiological depth cues include convergence, accommodation, binocular disparity, and motion parallax. Psychological depth cues include linear perspective, shadowing, shading, aerial perspective, occlusion, texture gradient and color. Computer graphics display devices render 3D scenes in a two-dimensional (2D) display space, relying on psychological cues to convey depth information. Stereoscopic cathode ray tube techniques which supply different images to the right and the left eye add limited stereopsis and require double rendering of images. Head mounted displays incorporated with the stereoscopic techniques add motion parallax and angles of view, but still require two sets of images and are physically intrusive.
Current 3D display techniques include using wires filling a volume in three space variables and illuminating a voxel in response to the voltage at the intersection of the wires; stacked 2D matrices of light emitting diodes activated by intersecting conductors; intersecting beams from two adjacent orthogonal matrices of light sources onto a medium within the volume which will only emit illumination when both beams are present, and a third orthogonal matrix of beams for returning the medium to its initial state; impinging a coherent light beam on a spinning surface, the volume being created as the surface moves quickly along a curve, typically helical; and illuminating a passive source with a rotating active matrix of light emitting diodes. In particular, U.S. Pat. Nos. 3,177,486, 3,668,639, 4,078,229, and 5,231,538 are hereby incorporated by reference.
Each of these techniques have their own advantages and disadvantages for particular applications. Most of these techniques are very weak in the area of providing a variety of colors to further encode the information being displayed thereby.